LAKE ELSINORE (CBSLA) – Lake Elsinore in Riverside County was open to swimmers and water sport enthusiasts over Labor Day Weekend despite the presence of algae blooms.

On Friday, the State Water Board reported that Lake Elsinore was one of several lakes throughout California which had received a danger advisory after testing revealed high levels of Harmful Algae Blooms (HAB). The SWB recommended that visitors not swim or make any direct water contact.

(CBS2)

Last week, signs went up at entrances all around the lake warning visitors about the algae. However, the lake itself was not closed, which created some confusion. The warnings also didn’t stop many visitors from getting out on the water.

Under the right environmental conditions, algae and cyanobacteria can grow into blooms that produce toxins, according to SWB. These cyanotoxins and algae toxins are harmful to people and animals. They can also accumulate in fish and shellfish.

As of Aug. 27, there were six reports of human illness and 12 reports of animal illness or death stemming from HABs in California, the water board reports.

HABs can look like a thick paint floating on the water and can come in several colors, including green, white, red or brown. Cyanobacteria blooms have a grainy, sawdust appearance. For more information, click here.